An X-ray imaging apparatus is a radiographic device which allows X-rays emitted by the collision of thermal electrons between a cathode and an anode to be transmitted through the body of a patient or an animal and develops the X-rays transmitted through the body of the patient or the animal on a film or a digital image panel to diagnose the health state of the patient or the animal. The X-ray imaging apparatus has been widely used as a device for simply and conveniently diagnosing the state of the fracture site of the patient or the animal, or whether the internal organs of the patient or the animal are abnormal without giving any pain to the patient or the animal. Recently, various techniques are developed to accurately photograph X-ray images of the patient or the animal in an easier-to-use manner.
Particularly, the X-ray imaging apparatus is manufactured in a mobile type so that the X-ray images of the patient or the animal can be photographed at a desired place anytime without being limited to place and time to directly diagnose the health state of the patient or the animal.
FIG. 1 is a functional block diagram illustrating a conventional mobile X-ray imaging apparatus using a commercial power supply according to the prior art.
The conventional mobile X-ray imaging apparatus will be described hereinafter in more detail with reference to FIG. 1.
Referring to FIG. 1, the conventional mobile X-ray imaging apparatus 1 includes a AC-DC converting unit 2 for converting commercial AC power inputted thereto into DC power, a DC-AC converting unit 3 for converting the DC power converted by fast switching into high-frequency AC power ranging from 20 KHz to 300 KHz, a high-voltage transformer 4 for boosting the converted high-frequency AC power to high-voltage AC power, and an AC-DC converting unit 5 for converting the boosted high-voltage AC power into high-voltage DC power for application to an X-ray tube 6. The X-ray tube 6 is operated such that electric current is applied to a cathode filament installed in a high-vacuum glass bulb to generate heated thermal electrons, and the heated thermal electrons are accelerated and collide with an anode as a positive electrode made of a metal material such as tungsten to generate X-rays by a potential difference applied to the X-ray tube from the AC-DC converting unit 5.
A sensor unit 7 senses the magnitude of voltage applied to the X-ray tube 6 and the magnitude of current flowing through the filament of the X-ray tube 6 to generate a sensed signal for application to a voltage control unit 8 and a current control unit 9. The voltage control unit 8 produces a pulse signal to control the magnitude of voltage based on the sensed signal applied thereto from the sensor unit 7 and controls the switching on/off cycle of the DC-AC converting unit 3 based on the produced pulse signal to control the frequency of the AC power converted and generated from the AC power by the AC converting unit 3. In addition, the current control unit 9 controls the magnitude of current outputted from a filament transformer 10 based on the sensed signal applied thereto from the sensor unit 7 to ultimately control the magnitude of current flowing through the X-ray tube 7.
FIG. 2 is a functional block diagram illustrating a conventional mobile X-ray imaging apparatus 20 using a battery as a power supply according to the prior art.
The conventional mobile X-ray imaging apparatus 20 will be described hereinafter in more detail with reference to FIG. 2.
Referring to FIG. 2, the conventional mobile X-ray imaging apparatus 20 includes a battery unit 21 consisting of a plurality of batteries serially connected to each other to output high-voltage DC power, a DC-AC converting unit 22 for converting the high-voltage DC power applied thereto from the battery unit 21 by fast switching into high-frequency AC power ranging from 20 KHz to 300 KHz, a high-voltage transformer 23 for boosting the converted high-frequency AC power to high-voltage AC power, an AC-DC converting unit 24 for converting the boosted high-voltage AC power into high-voltage DC power, and an X-ray tube 25 for generating X-rays using the high-voltage DC power applied thereto from the AC-DC converting unit 24.
The sensor unit 26, the voltage control unit 27, the current control unit 28, and the filament transformer 29 are operated in the same manner as that of the sensor unit 7, the voltage control unit 8, the current control unit 9, and the filament transformer 10 shown in FIG. 1 to control the magnitude of the DC voltage applied to the X-ray tube 25 and the magnitude of current applied to the filament of the X-ray tube 25.